A position information processing device uses a region name, a phone number, and an address to offer route guide information to a destination. The position information processing device has to determine an accurate current position so as to offer the route guide information to the destination from the current position.
Generally, the position information processing device for the vehicle uses a single position measuring method. The single position measuring method uses one GPS receiver receiving satellite signals from satellites and measures present latitude, longitude, and elevation through triangulation. The satellite signal includes position vector information of the satellite, and a position information processing device uses a time that it takes the satellite signal to reach the position information processing device and position vector information of the satellite to measure the current position.
When one GPS receiver is used, an error of the position measurement can range within a radius of about 10 m. The position information processing device for a vehicle uses a MAP-matching method that matches the measured position on an electronic map to be able to compensate the error range to a radius of about 3 m. That is, the position information processing device for the vehicle has an error range of about 3 m to offer route guide information to a driver. When the vehicle runs on an express way or a simple wide road, a relatively accurate route guide is possible with the above error range.
If the vehicle runs on a complicated road or a narrow road where there are several roads within the error range, it is difficult to use the MAP-matching method and the position information processing device does not offer an accurate route guide.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.